If the "United States" gives you a command, it may be evil. But there's still reasoning behind it. If an "AI King" gives you a command, well, it's simply guessing the next word in a sentence. In both cases you get a command, but they differ in how they were made.
You're really charitable to the "United States." There is approximately no reason behind what it does for the most part, it's just an AI made out of biological serfs.